na94

I recently purchased a 991 cup car that should have about 10 hours on 2 new axles. It appears that the right one has deposited a massive amount of grease from the inner CV onto the surrounding area, however the boot appears to be intact. The joint feels normal and does not have any noticeable play.

There is a bit of grease weeping from the interface between the boot and the CV, but nothing that explains the massive amount of grease that has been deposited. When seeing CV failures of this nature in the past, I have always found a shredded boot.

Is this a common failure mode for these axles, or is this possibly something that didn't get properly cleaned up? Pic attached for reference.

carbondan

See my post on the topic, I guess this is just the way it's meant to be.

https://rennlist.com/forums/porsche-...-to-clamp.html

na94

That makes sense, however the weep is on the CV side of the boot and not the shaft side. And there is a LOT of grease on the oil tank and frame. I guess I will just clear it off and monitor, and maybe try to add a little grease in with a dispenser. Maybe someone added too much at some point and it got expelled.

Ed@Demonspeed

That is a lot of grease. More than you should expect.

I would pull the shaft and inspect the boot for a cut of one type or another.

Best practice for the boot is to add a breather tube. The breather tube can be used in conjunction with the zip tie.

The idea of not clamping is so that it can breathe and move a bit on the shaft to avoid stretching or ballooning.

Thanks

Ed

Oddjob

This is for a 997:

I found fresh CV grease splatter after my first event this year, and thought I traced it to the large end clamp loose enough to not seal the boot. So I replaced that clamp.







Then at the next event, that same boot failed - big tear in the boot with grease all over the underside and speckling the back end of the car.

I worried that the joint was possibly failing and overheated, causing overpressure and bursting the boot. But I replaced the boot at the track on a Friday night, and then ran the car the next two days w/o issue. So I have to assume that the joint was ok and likely there was previously a small hole in the boot that I had missed.

So as recommended above, I'd inspect the boot closely for a pin hole or beginnings of a small cut/crack.

na94

Thanks guys, I'll go over it in detail and look for any signs of a split.

Does anyone bother to drill and safety wire the axle flange bolts, or is that overkill?

bgiere

Mine was doing the same...I used a cocktail stir as a breather tube and zip tied the boot end...haven't seen any grease since.

na94

I've removed the wheel lock and axle nut, as well as the transaxle flange bolts, but the outboard end does not want to come out of the hub. Do I need to use a puller on it?

Also, I don't see a torque spec for the axle nut in the technical manual. Can someone please post it?